diff -u b/core/modules/file/src/Plugin/Field/FieldFormatter/FileAudioFormatter.php b/core/modules/file/src/Plugin/Field/FieldFormatter/FileAudioFormatter.php
--- b/core/modules/file/src/Plugin/Field/FieldFormatter/FileAudioFormatter.php
+++ b/core/modules/file/src/Plugin/Field/FieldFormatter/FileAudioFormatter.php
@@ -25,9 +25,2 @@
 
-  /**
-   * {@inheritdoc}
-   */
-  protected function getHtmlTag() {
-    return static::getMediaType();
-  }
-
 }
diff -u b/core/modules/file/src/Plugin/Field/FieldFormatter/FileMediaFormatterBase.php b/core/modules/file/src/Plugin/Field/FieldFormatter/FileMediaFormatterBase.php
--- b/core/modules/file/src/Plugin/Field/FieldFormatter/FileMediaFormatterBase.php
+++ b/core/modules/file/src/Plugin/Field/FieldFormatter/FileMediaFormatterBase.php
@@ -15,12 +15,14 @@
 abstract class FileMediaFormatterBase extends FileFormatterBase implements FileMediaFormatterInterface {
 
   /**
-   * Gets the HTML tag for a formatter.
+   * Gets the HTML tag for the formatter.
    *
    * @return string
    *   The HTML tag of this formatter.
    */
-  abstract protected function getHtmlTag();
+  protected function getHtmlTag() {
+    return static::getMediaType();
+  }
 
   /**
    * {@inheritdoc}
@@ -121,7 +123,7 @@
     $attributes = $this->prepareAttributes();
     foreach ($source_files as $delta => $files) {
       $elements[$delta] = [
-        '#theme' => 'file_' . $this->getHtmlTag(),
+        '#theme' => $this->getPluginId(),
         '#attributes' => $attributes,
         '#files' => $files,
         '#cache' => ['tags' => []],
diff -u b/core/modules/file/src/Plugin/Field/FieldFormatter/FileVideoFormatter.php b/core/modules/file/src/Plugin/Field/FieldFormatter/FileVideoFormatter.php
--- b/core/modules/file/src/Plugin/Field/FieldFormatter/FileVideoFormatter.php
+++ b/core/modules/file/src/Plugin/Field/FieldFormatter/FileVideoFormatter.php
@@ -28,13 +28,6 @@
   /**
    * {@inheritdoc}
    */
-  protected function getHtmlTag() {
-    return static::getMediaType();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
   public static function defaultSettings() {
     return [
       'muted' => FALSE,
diff -u b/core/modules/file/tests/src/Functional/Formatter/FileAudioFormatterTest.php b/core/modules/file/tests/src/Functional/Formatter/FileAudioFormatterTest.php
--- b/core/modules/file/tests/src/Functional/Formatter/FileAudioFormatterTest.php
+++ b/core/modules/file/tests/src/Functional/Formatter/FileAudioFormatterTest.php
@@ -17,7 +17,6 @@
    * @dataProvider dataProvider
    */
   public function testRender($tag_count, $formatter_settings) {
-
     $field_config = $this->createMediaField('file_audio', 'mp3', $formatter_settings);
 
     file_put_contents('public://file.mp3', str_repeat('t', 10));
@@ -50,22 +49,10 @@
     $file1_url = file_url_transform_relative(file_create_url($file1->getFileUri()));
     $file2_url = file_url_transform_relative(file_create_url($file2->getFileUri()));
 
-    $this->assertSession()->elementsCount('css', 'audio[controls="controls"]', $tag_count);
-    $this->assertSession()->elementExists('css', "audio > source[src='$file1_url'][type='audio/mpeg']");
-    $this->assertSession()->elementExists('css', "audio > source[src='$file2_url'][type='audio/mpeg']");
-  }
-
-  /**
-   * Data provider for testRender.
-   *
-   * @return array
-   *   Provided data.
-   */
-  public function dataProvider() {
-    return [
-      [2, []],
-      [1, ['multiple_file_display_type' => 'sources']],
-    ];
+    $assert_session = $this->assertSession();
+    $assert_session->elementsCount('css', 'audio[controls="controls"]', $tag_count);
+    $assert_session->elementExists('css', "audio > source[src='$file1_url'][type='audio/mpeg']");
+    $assert_session->elementExists('css', "audio > source[src='$file2_url'][type='audio/mpeg']");
   }
 
 }
diff -u b/core/modules/file/tests/src/Functional/Formatter/FileMediaFormatterTestBase.php b/core/modules/file/tests/src/Functional/Formatter/FileMediaFormatterTestBase.php
--- b/core/modules/file/tests/src/Functional/Formatter/FileMediaFormatterTestBase.php
+++ b/core/modules/file/tests/src/Functional/Formatter/FileMediaFormatterTestBase.php
@@ -39,7 +39,7 @@
    *   The formatter ID.
    * @param string $file_extensions
    *   The file extensions of the new field.
-   * @param string[] $formatter_settings
+   * @param array $formatter_settings
    *   Settings for the formatter.
    *
    * @return \Drupal\field\Entity\FieldConfig
@@ -76,2 +76,18 @@
 
+  /**
+   * Data provider for testRender.
+   *
+   * @return array
+   *   An array of data arrays.
+   *   The data array contains:
+   *     - The number of expected HTML tags.
+   *     - An array of settings for the field formatter.
+   */
+  public function dataProvider() {
+    return [
+      [2, []],
+      [1, ['multiple_file_display_type' => 'sources']],
+    ];
+  }
+
 }
diff -u b/core/modules/file/tests/src/Functional/Formatter/FileVideoFormatterTest.php b/core/modules/file/tests/src/Functional/Formatter/FileVideoFormatterTest.php
--- b/core/modules/file/tests/src/Functional/Formatter/FileVideoFormatterTest.php
+++ b/core/modules/file/tests/src/Functional/Formatter/FileVideoFormatterTest.php
@@ -17,7 +17,6 @@
    * @dataProvider dataProvider
    */
   public function testRender($tag_count, $formatter_settings) {
-
     $field_config = $this->createMediaField('file_video', 'mp4', $formatter_settings);
 
     file_put_contents('public://file.mp4', str_repeat('t', 10));
@@ -50,22 +49,10 @@
     $file1_url = file_url_transform_relative(file_create_url($file1->getFileUri()));
     $file2_url = file_url_transform_relative(file_create_url($file2->getFileUri()));
 
-    $this->assertSession()->elementsCount('css', 'video[controls="controls"]', $tag_count);
-    $this->assertSession()->elementExists('css', "video > source[src='$file1_url'][type='video/mp4']");
-    $this->assertSession()->elementExists('css', "video > source[src='$file2_url'][type='video/mp4']");
-  }
-
-  /**
-   * Data provider for testRender.
-   *
-   * @return array
-   *   Provided data.
-   */
-  public function dataProvider() {
-    return [
-      [2, []],
-      [1, ['multiple_file_display_type' => 'sources']],
-    ];
+    $assert_session = $this->assertSession();
+    $assert_session->elementsCount('css', 'video[controls="controls"]', $tag_count);
+    $assert_session->elementExists('css', "video > source[src='$file1_url'][type='video/mp4']");
+    $assert_session->elementExists('css', "video > source[src='$file2_url'][type='video/mp4']");
   }
 
 }